Radiotherapy-assisted tumor selective metronomic oral chemotherapy.

Chemotherapy have commonly been used in maximum tolerated dose to completely eradicate the cancer. However, such treatments often failed due to the complex and dynamic nature of cancer. Therefore, it has been suggested that cancer should be treated as a chronic disease, controlling its growth by providing continuous therapeutic pressure for long-term. Such an approach, however, requires a therapy that is non-toxic and orally available with sufficient potency. Herein, we propose a radiotherapy-assisted orally available metronomic apoptosis-targeted chemotherapy, which delivers doxorubicin continuously to the irradiated tumor with high selectivity while causing minimal toxicities to the normal tissues. DEVD-S-DOX/DCK complex is the anticancer prodrug for our strategy that could selectively release doxorubicin in the irradiated tumor tissue with sufficient oral bioavailability. The prodrug was completely inactive by itself, but displayed potent anticancer activity when coupled with radiotherapy. Consequently, the daily oral administration of DEVD-S-DOX/DCK in combination with the low-dose radiotherapy effectively suppressed the growth of tumor in vivo with no significant systemic toxicities despite that the accumulated dose of doxorubicin exceeded 150 mg/kg. Therefore, the our novel therapy using DEVD-S-DOX/DCK complex is considered as an outstanding treatment option for treating cancer for long-term attributed to its oral availability and low-toxicity profile as well as the potent anticancer effect.

Safety studies on intravenous infusion of a potent angiogenesis inhibitor: taurocholate-conjugated low molecular weight heparin derivative LHT7 in preclinical models.

CONTEXT: As a class of angiogenesis inhibitors, heparin conjugates have shown significant effectiveness in several studies. OBJECTIVES: The purpose of our current study is to evaluate the effectiveness and safety of infusing the conjugate of low molecular weight heparin and taurocholate (LHT7), which has been developed as a potent angiogenesis inhibitor. METHODS: To evaluate its safety, the method of intravenous infusion was compared with its i.v. bolus administration. Intravenous infusion was administered at a rate of 400 µl/min/kg of body weight for 30 min. Pharmacokinetic (PK) analysis, organ accumulation, and plasma concentration profiles of LHT7 were measured. The anticancer effect of LHT7 was evaluated in murine and human xenograft models, and preclinical studies were performed in SD rats and beagle dogs. RESULTS: The results of the PK studies showed reduced organ accumulation in mice and the AUC(0-96 h) (area under the curve) was increased up to 1485 ± 125 h × µg/ml. The efficacy, at dose 1 mg/kg/2 d was higher for i.v. infusion than for i.v. bolus administration in both murine and human cancer models. The preclinical studies showed the safety dose of LHT7 is less than 20 mg/kg in SD rats and in the next safety analysis in beagle dogs showed that there were no organ-specific adverse effects in higher doses, such as, 12 mg/kg. LHT7 showed sustained effects with minimized adverse events when administered through i.v. infusion. CONCLUSIONS: LHT7 (i.v. infusion) could be safely used for further clinical development as a multi-targeting anti-angiogenic agent.

Enhanced Anti-Angiogenic Effect of Low Molecular Weight Heparin-Bile Acid Conjugates by Co-Administration of a Selective COX-2 Inhibitor.

PURPOSE: To overcome definite limitations of angiogenesis inhibitors such as insufficient therapeutic efficacy as a single drug and resisting or conflicting effect under chronic treatment, it is required to develop a new regimen to improve the therapeutic effect. METHODS: The combination effect of a multi-targeting angiogenesis inhibitor (LHT7) and a selective cyclooxygenase-2 inhibitor (celecoxib) on neovascularization in tumor growth was studied both in vitro and vivo experiments. RESULTS: While hypoxia-mediated COX-2 overexpression and macrophage recruitment were observed at LHT7-treated tumor tissues, it was well-controlled by the combination of celecoxib and LHT7. On the other hand, the in vitro tube formation and the in vivo tumor vessel formation and structure were inhibited by either LHT7 or celecoxib, but the inhibition effect was further enhanced by using them together. However, the combination therapy did not further enhance the inhibitory effect on tumor growth in terms of volume compared to single drug uses, which attributed not to increased cellular apoptosis but to decreased cell proliferation. CONCLUSIONS: COX-2 inhibition could enhance the therapeutic effect of anti-angiogenic drugs both by inhibiting the inflammatory reactions induced by hypoxia and by altering the vascular stabilization that is mediated by an assembly with mural cells.

Preliminary safety evaluation of a taurocholate-conjugated low-molecular-weight heparin derivative (LHT7): a potent angiogenesis inhibitor.

In our previous studies, taurocholic acid (TA)-conjugated low-molecular-weight heparin derivative (LHT7) has been proven to be a potent anti-angiogenic agent by demonstrated successful blockage capability of vascular endothelial growth factors (VEGF). Preliminary safety evaluations were conducted based on its mechanism of action and chemical behavior. For this purpose, acute toxicity study, and hematological and serological evaluations were carried out. Additionally, in order to evaluate mechanism-related side effects, both blood pressure and the occurrence of proteinuria were measured using a treatment regime of multiple high doses of LHT7 in a biodistribution study. LD50 values for LHT7 in female and male mice were 56.9 and 64.7 mg kg(-1) doses, respectively. There were no vital fluctuations in the serological and hematological parameters, except for the elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) at 100 and 200 mg kg(-1) doses of LHT7, representing vital changes in the liver function. Moreover, the results of mechanism-related studies showed that blood pressure at 50 mg kg(-1) did not change but showed elevated levels of protein in urine. In the biodistribution study, a slight accumulation of LHT7 in the kidney and the liver were observed at the 50 mg kg(-1) repeated dose owing to the presence of bile acid. No fatal damage was observed in this study; most observations were related to the chemical composition or the mechanism of action of the material.

Combinational chemoprevention effect of celecoxib and an oral antiangiogenic LHD4 on colorectal carcinogenesis in mice.

To achieve a clinically rational regimen for cancer chemoprevention with improved efficacy and safety, the combination effect of celecoxib and newly developed oral angiogenesis inhibitor, LHD4, on chemoprevention was evaluated. The chemopreventive effects of celecoxib, LHD4, and the combination of celecoxib and LHD4 were evaluated in a murine colorectal carcinogenesis model. After 17 experimental weeks, mouse colon tissues were collected and examined in terms of polyp volume and degree of carcinogenesis, inflammation, and angiogenesis. Mice in the celecoxib-treated or LHD4-treated groups had total polyp volumes of 47.0±9.7 and 120.1±45.2 mm, respectively, which represented decreases of 65.6 and 22.3% from the control (154.5±33.5 mm). However, the polyp volume in the combination group was 22.8±9.3 mm, a decrease of 85.2% from the control. In the comparison of carcinogenesis, the percentage of normal tissue (i.e. excluding proliferative tissue) was found to be 40.6% in the control, 51.7% in the celecoxib, 56.9% in the LHD4, and 81.7% in the combination group. In accordance with attenuated carcinogenesis, both inflammation and angiogenesis were also well controlled. Together, these results suggest that the combinatory use of celecoxib and a newly developed oral heparin conjugate could be a promising regimen for chemoprevention by intervening in both inflammation and angiogenesis.

Stimulating macropinocytosis of peptide-drug conjugates through DNA-dependent protein kinase inhibition for treating KRAS-mutant cancer.

KRAS-mutant cancers, due to their protein targeting complexity, present significant therapeutic hurdles. The identification of the macropinocytic phenotype in these cancers has emerged as a promising alternative therapeutic target. Our study introduces MPD1, an macropinocytosis-targeting peptide-drug conjugates (PDC), which is developed to treat KRAS mutant cancers. This PDC is specifically designed to trigger a positive feedback loop through its caspase-3 cleavable characteristic. However, we observe that this loop is hindered by DNA-PK mediated DNA damage repair processes in cancer cells. To counter this impediment, we employ AZD7648, a DNA-PK inhibitor. Interestingly, the combined treatment of MPD1 and AZD7648 resulted in a 100% complete response rate in KRAS-mutant xenograft model. We focus on the synergic mechanism of it. We discover that AZD7648 specifically enhances macropinocytosis in KRAS-mutant cancer cells. Further analysis uncovers a significant correlation between the increase in macropinocytosis and PI3K signaling, driven by AMPK pathways. Also, AZD7648 reinforces the positive feedback loop, leading to escalated apoptosis and enhanced payload accumulation within tumors. AZD7648 possesses broad applications in augmenting nano-sized drug delivery and preventing DNA repair resistance. The promising efficacy and evident synergy underscore the potential of combining MPD1 with AZD7648 as a strategy for treating KRAS-mutant cancers.

Nanofiber-based glaucoma drainage implant improves surgical outcomes by modulating fibroblast behavior.

Biomaterials are implanted in millions of individuals worldwide each year. Both naturally derived and synthetic biomaterials induce a foreign body reaction that often culminates in fibrotic encapsulation and reduced functional lifespan. In ophthalmology, glaucoma drainage implants (GDIs) are implanted in the eye to reduce intraocular pressure (IOP) in order to prevent glaucoma progression and vision loss. Despite recent efforts towards miniaturization and surface chemistry modification, clinically available GDIs are susceptible to high rates of fibrosis and surgical failure. Here, we describe the development of synthetic, nanofiber-based GDIs with partially degradable inner cores. We evaluated GDIs with nanofiber or smooth surfaces to investigate the effect of surface topography on implant performance. We observed in vitro that nanofiber surfaces supported fibroblast integration and quiescence, even in the presence of pro-fibrotic signals, compared to smooth surfaces. In rabbit eyes, GDIs with a nanofiber architecture were biocompatible, prevented hypotony, and provided a volumetric aqueous outflow comparable to commercially available GDIs, though with significantly reduced fibrotic encapsulation and expression of key fibrotic markers in the surrounding tissue. We propose that the physical cues provided by the surface of the nanofiber-based GDIs mimic healthy extracellular matrix structure, mitigating fibroblast activation and potentially extending functional GDI lifespan.

Caspase-3 mediated switch therapy of self-triggered and long-acting prodrugs for metastatic TNBC.

Triple-negative breast cancer (TNBC) is characterized by its highly heterogeneous microenvironment and propensity for aggressive behavior, both of which represent, along with poor prognosis and high incidence of relapse, the main challenges of curing the disease. Although recent progress in targeted chemotherapy combinations has shown promising outcomes, conventional targeted chemotherapeutic approaches have relied on exploiting the expression of certain molecules or proteins overexpressed on cancer cells as drug targets, which have demonstrated limited clinical benefit against metastatic cancers. Here, we describe a tumoral caspase-3 mediated peptide-doxorubicin conjugates (PDC) switch therapy that adopts two different caspase-3 cleavable PDCs, RGDEVD-DOX (TPD1) and EMC-KGDEVD-DOX (MPD1), for targeting metastatic triple-negative breast cancer (mTNBC). First, using TPD1, an integrin αVß3 based targeted strategy was utilized to target tumor cells or tumor vasculature associated with the highly malignant progression of mTNBC. TPD1 triggered the tumor cell-specific initial apoptosis and the induction of caspase-3 expression in the target tumor site. Then MPD1 was administered sequentially, which is an albumin-binding prodrug, and activated by induced caspase-3 in order to maintain the tumoral caspase-3 level and release the cytotoxic payload. The PDC switch therapy markedly accumulated doxorubicin in the tumor site and augmented tumor-specific in situ amplification of apoptosis. Importantly, the PDC switch therapy exerted a bystander killing effect on the neighboring cancer cells thus demonstrating potent therapeutic efficacy against both local and metastatic cancers. Given the limited therapeutic outcomes with conventional targeted therapies, our strategy of regulating the expression of caspase-3 level as a drug target could provide as a more durable and effective alternative in the treatment of highly heterogeneous mTNBC.

Metronomic dose-finding approach in oral chemotherapy by experimentally-driven integrative mathematical modeling.

In conventional chemotherapy, maximum tolerated dose approach is considered as a first-line medication for cancer treatment in clinics. In contrast to the conventional chemotherapy which has heavy tumor burdens arising from high dose treatment, metronomic chemotherapy (MCT) engages relatively low dose without drug-free breaks, and is recognized as a promising strategy for a long-term management of the disease. Although doxorubicin (DOX), an anthracycline anti-cancer drug, showed a potential of maintenance effect in vitro, further study on in vivo-relevant concentration to achieve tumor suppression with no toxicity is required to apply the MCT in clinicals. Therefore, the objective of this study was to identify an optimal MCT regimen of DOX by determining concentration-response relationships of tumor suppression (pharmacodynamic; PD) and cardiac toxicity (toxicodynamic; TD). Utilizing an oral DOX formulation complexed with deoxycholic acid (DOX/DOCA complex) which has enhanced bioavailability, physiologically-based pharmacokinetic (PBPK) model was linked to TD and PD models to generate drug profiles from the combined PK, TD, and PD parameters. The integrated model was validated for various scenarios of administration route, formulation, dose, and frequency. The established mathematical model facilitated calculations of adequate in vivo-relevant dosages and intervals, suggesting the optimum oral metronomic regimen of DOX. It is expected to serve as a useful guideline for the design and evaluation of oral DOX formulations in future preclinical/clinical studies.

Feedback amplification of senolysis using caspase-3-cleavable peptide-doxorubicin conjugate and 2DG.

Therapy-induced senescence (TIS), a common outcome of current cancer therapy, is a known cause of late recurrence and metastasis and thus its eradication is crucial for therapy success. In this study, we introduced a conceptually novel strategy combining radiation-induced apoptosis-targeted chemotherapy (RIATC) with an effective glycolysis inhibitor, 2-deoxy-d-glucose (2DG) to target TIS. RIATC releases cytotoxic payload by amplification, continually increasing TIS, and this can be targeted by 2DG that stimulates an intrinsic apoptotic pathway in senescent cells, the senolysis; the senolytic 2DG also sensitizes cancer cells to chemo/radiation treatment. Anti-tumor efficacy of RIATC was investigated in numerous tumor models, and various cancer types were screened for TIS. Furthermore, in vitro evaluations of molecular markers of senescence, such as senescence-associated ß-galactosidase (SA-ß-Gal) assay, were performed to confirm that TIS was induced by RIATC therapy in MCF-7 cells. The combination therapy with 2DG proved to be effective in MCF-7 tumor-bearing mice that demonstrated feedback amplification of senolysis and successful inhibition of tumor growth. Our findings suggest that RIATC, when given together with 2DG, can overcome therapy-induced senescence and this combination is a promising strategy that enhances the therapeutic benefit of anti-cancer cytotoxic therapy.

Albumin metabolism targeted peptide-drug conjugate strategy for targeting pan-KRAS mutant cancer.

Despite recent breakthroughs in the development of direct KRAS inhibitors and modulators, no drugs targeting pan-KRAS mutant cancers are clinically available. Here, we report a novel strategy to treat pan-KRAS cancers using a caspase-3 cleavable peptide-drug conjugate that exploits enhanced albumin metabolism in KRAS altered cancers to deliver a cytotoxic agent that can induce a widespread bystander killing effect in tumor cells. Increased albumin metabolism in KRAS mutant cancer cells induced apoptosis via the intracellular uptake of albumin-bound MPD1. This allowed caspase-3 upregulation activated MPD1 to release the payload and exert the non-selective killing of neighboring cancer cells. MPD1 exhibited potent and durable antitumor efficacy in mouse xenograft models with different KRAS genotypes. An augmentation of anti-cancer efficacy was achieved by the bystander killing effect derived from the caspase-3 mediated activation of MPD1. In summary, albumin metabolism-induced apoptosis, together with the bystander killing effect of MPD1 boosted by caspase-3 mediated activation, intensified the efficacy of MPD1 in KRAS mutant cancers. These findings suggest that this novel peptide-drug conjugate could be a promising breakthrough for the treatment in the targeting of pan-KRAS mutant cancers.

Targeting angiogenic growth factors using therapeutic glycosaminoglycans on doppel-expressing endothelial cells for blocking angiogenic signaling in cancer.

Growth factors (GF) regulate normal development to cancer progression. GFs interact with extracellular matrix (ECM) biomolecules, such as heparin sulfate (HS) glycosaminoglycan (GAG), to enhance their stability and angiogenic signaling. Biomaterials that modulate GF activity by mimicking interactions observed in the native ECM could be designed as an effective treatment strategy. However, these materials failed to attenuate angiogenic signaling site-specifically without sparing normal tissues. In this work, we investigated the effect of a GAG-based biomaterial, which binds to the tumor endothelial cells (TEC), on the interaction among vascular endothelial growth factor (VEGF), its receptors-VEGFR2 and HS-and angiogenesis. Heparin-bile acid based conjugates, as ECM-mimicking component, were synthesized to selectively target the TEC marker doppel and doppel/VEGFR2 axis. The most effective compound LHbisD4 (low molecular weight heparin conjugated with 4 molecules of dimeric dexocholic acid) reduced tumor volume concentrated over doppel-expressing EC, and decreased tumor-interstitial VEGF without affecting its plasma concentration. Doppel-destined LHbisD4 captured VEGF, formed an intermediate complex with doppel, VEGFR2, and VEGF but did not induce active VEGFR2 dimerization, and competitively inhibited HS for VEGF binding. We thus show that GAG-based materials can be designed to imitate and leverage to control tumor microenvironment via bio-inspired interactions.

Sustained potentiation of bystander killing via PTEN-loss driven macropinocytosis targeted peptide-drug conjugate therapy in metastatic triple-negative breast cancer.

While conventional approaches for PTEN-loss cancers mainly focus on turning off growth promoting process through modulation of PI3K/AKT pathways, no effective therapeutic treatments that target PTEN-loss cancer cells have yielded results. Moreover, conventional targeted therapies, which are potent against only a subset of cancer cells with limited specificity, bring on temporary response. Here, we report the development of albumin-binding caspase-3 cleavable peptide-drug conjugate (PDC), which utilizes the enhanced albumin metabolism pathway in PTEN-loss cancer cells to enhance the intracellular delivery of chemotherapeutic payload that could exert a bystander killing effect. Albumin metabolism-mediated apoptosis triggered expression of caspase-3 allows the continuous activation of the PDC, accumulation of payloads, sustained upregulation of tumoral caspase-3, and intensified in-situ apoptosis. Importantly, PDC strategy exerts potent therapeutic efficacy against PTEN-loss metastatic triple-negative breast cancer, the highly aggressive and heterogenous nature of which remains a challenge conventional targeted therapies need to overcome. This study thus presents a conceptually novel approach to treat PTEN-loss cancer and creates new translational perspectives of exploiting PTEN-loss for providing an avenue to advance current targeted therapy.

Overcoming physical stromal barriers to cancer immunotherapy.

Immunotherapy has emerged as an unprecedented hope for the treatment of notoriously refractory cancers. Numerous investigational drugs and immunotherapy-including combination regimens are under preclinical and clinical investigation. However, only a small patient subpopulation across different types of cancer responds to the therapy due to the presence of several mechanisms of resistance. There have been extensive efforts to overcome this limitation and to expand the patient population that could be benefited by this state-of-the-art therapeutic modality. Among various causes of the resistance, we here focus on physical stromal barriers that impede the access of immunotherapeutic drug molecules and/or native and engineered immune cells to cancer tissues and cells. Two primary stromal barriers that contribute to the resistance include aberrant tumor vasculatures and excessive extracellular matrix build-ups that restrict extravasation and infiltration, respectively, of molecular and cellular immunotherapeutic agents into tumor tissues. Here, we review the features of these barriers that limit the efficacy of immunotherapy and discuss recent advances that could potentially help immunotherapy overcome the barriers and improve therapeutic outcomes.

Keratin 19 interacts with GSK3ß to regulate its nuclear accumulation and degradation of cyclin D3.

Cyclin D3 regulates the G1/S transition and is frequently overexpressed in several cancer types including breast cancer, where it promotes tumor progression. Here we show that a cytoskeletal protein keratin 19 (K19) physically interacts with a serine/threonine kinase GSK3ß and prevents GSK3ß-dependent degradation of cyclin D3. The absence of K19 allowed active GSK3ß to accumulate in the nucleus and degrade cyclin D3. Specifically, the head (H) domain of K19 was required to sustain inhibitory phosphorylation of GSK3ß Ser9, prevent nuclear accumulation of GSK3ß, and maintain cyclin D3 levels and cell proliferation. K19 was found to interact with GSK3ß and K19-GSK3ß interaction was mapped out to require Ser10 and Ser35 residues on the H domain of K19. Unlike wildtype K19, S10A and S35A mutants failed to maintain total and nuclear cyclin D3 levels and induce cell proliferation. Finally, we show that the K19-GSK3ß-cyclin D3 pathway affected sensitivity of cells toward inhibitors to cyclin-dependent kinase 4 and 6 (CDK4/6). Overall, these findings establish a role for K19 in the regulation of GSK3ß-cyclin D3 pathway and demonstrate a potential strategy for overcoming resistance to CDK4/6 inhibitors.

Caspase-cleavable peptide-doxorubicin conjugate in combination with CD47-antagonizing nanocage therapeutics for immune-mediated elimination of colorectal cancer.

Here we report a novel combination of a caspase-cleavable peptide-doxorubicin conjugate (MPD-1) with CD47-antagonizing nanocage therapeutics for the treatment of microsatellite-stable (MSS) colorectal cancer (CRC). MPD-1 (i) upregulated markers of immunogenic cell death (ICD) in tumor, and increased co-stimulatory markers on dendritic cells (DCs), (ii) enhanced CD8+ T cell infiltration and antigen presenting cell (APC) activation, and (iii) showed negligible off-target immune-related toxicity compared to free dox. Then, the CD47 antagonist FS nanocage, a SIRPα-expressing ferritin nanocage, was co-administered with MPD-1 that resulted in 95.2% (p < 0.001) tumor growth inhibition in an established CRC model. T cell-mediated elimination of tumors was also confirmed by the tumor-specific activation of T cells detected by IFNγ and tumor-free mice were observed (95%) that bared a memory response when re-challenged. The strategically developed MPD-1 is an ideal adjuvant to immunotherapy and the combination with FS nanocage triggers potent immunity against MSS CRC. In summary, we present an approach to initiate and stimulate immune-mediated eradication of cancer cells using synergistic immunogenic agents targeting the MSS CRC.

Dual mechanistic TRAIL nanocarrier based on PEGylated heparin taurocholate and protamine which exerts both pro-apoptotic and anti-angiogenic effects.

The selective cytotoxicity of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) to cancer cells but not to normal cells makes it an attractive candidate for cancer therapeutics. However, the disadvantages of TRAIL such as physicochemical instability and short half-life limit its further clinical applications. In this study, TRAIL was encapsulated into a novel anti-angiogenic nanocomplex for both improved drug distribution at the tumor site and enhanced anti-tumor efficacy. A nanocomplex was prepared firstly by entrapping TRAIL into PEG-low molecular weight heparin-taurocholate conjugate (LHT7), which is previously known as a potent angiogenesis inhibitor. Then, protamine was added to make a stable form of nanocomplex (PEG-LHT7/TRAIL/Protamine) by exerting electrostatic interactions. We found that entrapping TRAIL into the nanocomplex significantly improved both pharmacokinetic properties and tumor accumulation rate without affecting the tumor selective cytotoxicity of TRAIL. Furthermore, the anti-tumor efficacy of nanocomplex was highly augmented (73.77±4.86%) compared to treating with only TRAIL (18.49 ± 19.75%), PEG-LHT7/Protamine (47.84 ± 14.20%) and co-injection of TRAIL and PEG-LHT7/Protamine (56.26 ± 9.98%). Histological analysis revealed that treatment with the nanocomplex showed both anti-angiogenic efficacy and homogenously induced cancer cell apoptosis, which suggests that accumulated TRAIL and LHT7 in tumor tissue exerted their anti-tumor effects synergistically. Based on this study, we suggest that PEG-LHT7/Protamine complex is an effective nanocarrier of TRAIL for enhancing drug distribution as well as improving anti-tumor efficacy by exploiting the synergistic mechanism of anti-angiogenesis.

Anticoagulation therapy promotes the tumor immune-microenvironment and potentiates the efficacy of immunotherapy by alleviating hypoxia.

PURPOSE: Here, this study verifies that cancer-associated thrombosis (CAT) accelerates hypoxia, which is detrimental to the tumor immune microenvironment by limiting tumor perfusion. Therefore, we designed an oral anticoagulant therapy to improve the immunosuppressive tumor microenvironment and potentiate the efficacy of immunotherapy by alleviating tumor hypoxia. EXPERIMENTAL DESIGN: A novel oral anticoagulant (STP3725) was developed to consistently prevent CAT formation. Tumor perfusion and hypoxia were analyzed with or without treating STP3725 in wild-type and P selectin knockout mice. Immunosuppressive cytokines and cells were analyzed to evaluate the alteration of the tumor microenvironment. Effector lymphocyte infiltration in tumor tissue was assessed by congenic CD45.1 mouse lymphocyte transfer model with or without anticoagulant therapy. Finally, various tumor models including K-Ras mutant spontaneous cancer model were employed to validate the role of the anticoagulation therapy in enhancing the efficacy of immunotherapy. RESULTS: CAT was demonstrated to be one of the perfusion barriers, which fosters immunosuppressive microenvironment by accelerating tumor hypoxia. Consistent treatment of oral anticoagulation therapy was proved to promote tumor immunity by alleviating hypoxia. Furthermore, this resulted in decrease of both hypoxia-related immunosuppressive cytokines and myeloid-derived suppressor cells while improving the spatial distribution of effector lymphocytes and their activity. The anticancer efficacy of αPD-1 antibody was potentiated by co-treatment with STP3725, also confirmed in various tumor models including the K-Ras mutant mouse model, which is highly thrombotic. CONCLUSIONS: Collectively, these findings establish a rationale for a new and translational combination strategy of oral anticoagulation therapy with immunotherapy, especially for treating highly thrombotic cancers. The combination therapy of anticoagulants with immunotherapies can lead to substantial improvements of current approaches in the clinic.

Polyproline-type helical-structured low-molecular weight heparin (LMWH)-taurocholate conjugate as a new angiogenesis inhibitor.

Although heparin can regulate angiogenesis, tumor growth and metastasis, its clinical application, as well as that of low-molecular heparin (LMWH), for treating cancer are limited because of heparin's anticoagulant activity and risk of hemorrhages. LMWH-taurocholate conjugates (LHT7), which have low anticoagulant activity, were synthesized. The structural property of LHT was evaluated by circular dichroism and the binding affinity of LHT7 to vascular endothelial growth factor 165 (VEGF(165)) was measured by isothermal titration calorimetry. The inhibitory effect of LHT7 on VEGF-mediated KDR (VEGF-receptor 2) phosphorylation in Human umbilical vein endothelial cells was evaluated. The VEGF(165) dependent Matrigel plug assay was performed to verify the antiangiogenic potential of LHT7 on a VEGF(165) inhibitor. Finally, tumor growth inhibition effects of LHT7 on SCC7 and the survival rate of animal models were investigated. Moreover, MDA-MB231 xenograft mouse model was additionally used to confirm the therapeutic effect of LHT7 on human breast cancer cell line. As a result, LHT7 which has 12.7% of anticoagulant activity of the original LMWH showed a peculiar polyproline-type helical structure. LHT7 binds to VEGF strongly and inhibits VEGF dependent KDR phosphorylation. The results of Matrigel plug assay proved LHT7 as a strong antiangiogenic agent inhibiting VEGF(165). Remarkably, LHT7 showed a significant tumor growth inhibition potential on SCC7 with an increased survival rate. LHT7 also delayed tumor growth in MDA-MB231 human breast cancer cell lines.

Highly potent monomethyl auristatin E prodrug activated by caspase-3 for the chemoradiotherapy of triple-negative breast cancer.

Despite the emergence of advanced therapeutics such as targeted therapy and immunotherapy in the modern oncology, cytotoxic chemotherapy still remains as the first-line treatment option in a wide range of cancers attributing to its potency. Many endeavors have been made to overcome the toxicity issues of cytotoxic chemotherapy by improving the specific delivery to the tumor, with active tumor targeting being one of the most popular approaches. However, such an approach has been challenged by the intratumor heterogeneity and the lack of valid molecular target in many types of cancer. Here, we introduce a novel albumin-binding prodrug MPD02 that could specifically deliver highly potent cytotoxin monomethyl auristatin E (MMAE) to the tumor as an important component of chemoradiotherapy for the treatment of triple-negative breast cancer (TNBC). MPD02 was synthesized by conjugating MMAE to the C-terminus of the KGDEVD peptide via self-eliminating linker and introducing a maleimide group to the Lys side chain of the peptide. MPD02 was able to bind albumin after administration via maleimide group for an extended circulation time and metabolized into MMAE in tumor-specific manner by reacting with the caspase-3 upregulated in tumor by radiotherapy, exerting a highly potent anticancer effect with good safety profile in two different TNBC xenograft models.